Q  C 

291 


GIFT  OF 
Harry  East  Miller 


T 


AMERICAN  METER  C 


NEW    YORK 
PHILADBL.PH  lA    -    CHICAGO 


CALORIMETRY 


ESTABLISHED     1S34 


Xhe   American   M[eter   Go* 

ELEVENTH  AVE.  and  47th  ST. 
NEW  YORK 

CHICAGO  PHILADELPHIA 

Peoples  Gas  Building  Arch  and  22nd  Sts, 

1914 


CONTENTS. 

Calorimetry    3 

Calorimeters 

German  Junkers  6 

American  Junkers   7 

Line  Cut  of  American  Junkers  Calorimeter  10 

General  Description  and   Improvements  11 

Detail  of  Complete  Outfits  ....12 


Accessories 


Carrying  Cases  15 

Barometer    15 

Hygrometer    ( Hygrodeik) 15 

Meter  Testing  Bottle  15 

Automatic  Gas  Shut-off  ....16 

Line    Cut 17 

Tests  by  Public  Service  Commission  2nd  Dist.,  New  York 18 

Favorable  Features  and  Guarantee  18 

Recommendations  of  American  Gas  Institute 

Definition  of  Heating  Value  19 

Gross  and  Theoretical  Total  Heating  Value  19 

Net  Heating  Value  20 

English  Measuring  System — B.  t.  u's  20 

Specifications  of  American  Gas  Institute   for  a   Junkers  Calori- 

/^\          A.t^^  •••  •  •  ••        •  •        •  • 

meter  Outfit          .:  •  •    *. ::::::  : 

Calorimeter    ;  %v    ,  V  I  ;*;  :./ 21 

Meter    .v::.:  .•*..,*«•: *.....*....,,,  22 

Gas  Pressure  Rfegtulattfr  V:  I  i  'M :  /A  ¥  .? 23 

Burners    ' *."..*....".  23 

Thermometers  24 

Barometer   25 

Water  Supply  and  Measurement  ...  25 

Gas  Piping  and  Tubing  26 

Calorimeter  Cabinet  26 

Directions  for  Erecting  and  Operating 28 

Record   Card  32 

Use  of  Computer  33 

Care  of  Instruments  34 

Precautions — Don'ts  34 

Adjusting  Thermometers   35 

Adjusting  Balance  35 

Corrections  for  Humidity  36 

Directions  for  use  of  Accessory  Apparatus 

Observatory  Barometer  37 

Hygrodeik    38 

One-Tenth  Cubic  Foot  Bottle  ..  39 


A 


^v 


In  the  beginning  the  gas  industry  was  devoted  to  illumination 
only  and  for  many  years  every  effort  was  made  to  improve  the  light 
giving  qualities  of  gas  and  to  devise  the  best  burners  which  could 
be  invented  for  bringing  out  those  qualities. 

The  science  of  photometry  was  then  developed  to  measure  by 
comparison  with  an  accepted  standard  the  amount  of  light  obtain- 
able from  a  given  quantity  of  the  gas  tested. 

Later,  gas  being  found  useful  for  heating  and  cooking  and  for 
numerous  industrial  purposes,  its  thermal  or  heat  producing  quality 
became  important.  With  the  introduction  of  incandescent  mantles 
for  gas  lighting,  the  heating  value  began  to  assume  greater  im- 
portance than  the  illuminating  power  and  as,  at  present,  80%  to 
90%  of  the  gas  sold  is  used  for  its  heat,  the  fairest  test  of  its  value 
to  the  majority  of  consumers  is  the  determination  of  its  heating 
quality. 

This  cannot  be  deduced  from  the  results  of  photometric  tests  as 
there  is  no  definite  relationship  between  the  light  and  the  heat  giving 
qualities,  it  being  possible  to  change  the  composition  of  the  gas 
materially,  substituting  one  non-illuminant  of  high  heating  value 
for  another  giving  much  less  heat  without  causing  any  decided 
change  in  the  candle  power.  Therefore,  the  heat  producing  or 
calorific  value  must  be  sought  by  other  means. 

This  is  the  science  of  calorimetry — the  measurement  of  heat. 


M82511 


As  in  photometry,  there  is  a  unit  of  measurement  or  standard 
of  comparison,  this  heat  unit  being  called  in  countries  where  the 
metric^  system  of :weighte  and  measures  is  in  general  use,  a  "Calorie," 
and  wrTdfe  trfe  "English  system  prevails,  as  in  this  country,  the 
^riiishj  tkirniar  unit,  .usually  abbreviated  to  B.  t.  u. 

The  Calorie  as  a  heat  unit  may  be  large  or  small :  the  large  ( Kg- 
calorie,  written  also,  Calorie,  with  a^  capital  C),  representing  the 
amount  of  heat  necessary  to  raise  the  temperature  of  i  kilogram  of 
water  at  its  greatest  density  i°  Centigrade  and  the  small  (g.-calorie, 
written  also,  calorie,  with  a  small  c),  the  amount  required  to  raise 
the  temperature  of  i  gram  of  water  i°  Centigrade. 

The  British  thermal  unit  represents  the  amount  of  heat  necessary 
to  raise  the  temperature  of  i  pound  of  water  at  its  point  of  greatest 
density  i°  Fahrenheit.  In  practice,  however,  the  standard  for 
density  is  based  on  a  temperature  of  60°  F.  and  a  barometric  pres- 
sure of  30  inches. 

The  number  of  heat  units  obtainable  from  a  given  gas  can  be 
determined  by  chemical  analysis  but,  while  theoretically  a  perfect 
method,  it  will  not  do  for  every-day  practice  by  gas  companies  and 
government  inspectors,  as  the  process  is  too  slow  and  expensive  and 
a  skilled  chemist  must  be  engaged  for  the  purpose. 

Therefore,  inventive  genius  has  designed  a  number  of  forms  of 
npparatus,  called  calorimeters,  for  determining  the  heating  value 
quickly  and  accurately  and  in  a  simple  manner  not  requiring  oper- 
ation by  an  expert. 


The  degree  of  accuracy  with  which  any  one  of  these  instruments 
Indicates  the  number  of  heat  units,  that  is,  its  efficiency,  depends  not 
so  much  on  the  operator  as  on  perfection  of  design  and  construction. 

In  this  respect  calorimetry  has  the  merit  over  photometry  of  giv- 
ing a  truer  indication  of  the  quality  of  the  gas,  as  the  personal  factor 
so  variable  in  making  observations  of  the  photometer  sight  box  disc 
lor  the  point  of  equal  illumination  is  practically  excluded  in  calor- 
imetry, the  determination  under  proper  working  conditions  being 
based  entirely  on  the  results  of  mechanical  operations,  viz.,  noting 
thermometer  and  barometer  indications,  weighing  the  water  heated 
arid  measuring  the  gas  consumed.  These  tests  may  be  very  accur- 
ately made,  with  a  little  practice,  by  any  intelligent  employee  of  the 
gas  company. 


CALORIMETERS. 

There  are  many  different  types  of  calorimeters  based  on  entirely 
different  principles,  some  applying  the  heat  of  the  gas  being  tested 
directly  to  water  running  through  the  instrument,  and  others  apply- 
ing it  to  some  other  medium. 

The  most  important  and  most  used  of  the  former  class,  viz.,  the 
continuous  flow,  water-heater  type,  is  the  Junkers  design. 

ORIGINAL   JUNKERS    CALORIMETER. 

The  original  German  form  of  this  instrument  has  been  in  exten- 
sive use  in  Europe  and  America  for  many  years  and  on  account  of 
its  high  efficiency  has  been  generally  favored  by  the  experts. 

In  the  proceedings  of  the  American  Gas  Institute  for  1908  and 
1909  are  found  complete  reports  of  investigations  carried  out  by 
and  under  the  direction  of  Prof.  Kowalke  of  the  Chemical  Engineer- 
ing Department  of  the  University  of  Wisconsin. 

We  quote  the  following  in  reference  to  the  original  German 
J unkers  Calorimeter : 

Among  many  conclusions  drawn  from  these  investi- 
gations the  following  are  especially  important. 

(a)  The  efficiency  of  the  Junkers  Calorimeter  is  99.5 
per  cent,  when  operating  conditions  are  as  follows: 

( 1 )  Temperature  of  inlet  water  and  exhaust  gases 
the  same  as  that  of  the  room,  when  applying  elec- 
trical energy. 

(2)  Rate  of  combustion  of  the  gas  from  7l/2  to 
Sy2  cubic  feet  per  hour. 

(3)  Difference  in  temperature  between  inlet  and 
outlet  water  from  15  to  16  degrees  F. 

(b)  The  most  extreme  variations  in  humidity  of  gas 
and  air  supply  may  cause  variations  in  heating  value  of 
from  — 5.90  B.  t.  u.  per  cubic  foot  to  +0.858  B.  t.  u. 
per  cubic  foot.     (All  gas  volumes  measured  at  60  de- 
grees F.  and  30  inches  of  mercury.) 

(c)  The  Junkers  calorimeter  is  the  most  desirable 
calorimeter  for  the  determination  of  the  heating  value 
of  municipal  gas. 

(d)  The  meter  should  be  frequently  calibrated. 

(e)  High  grade  thermometers  should  be  used. 


In  these  reports,  however,  it  was  recommended  that  changes  and 
improvements  be  made  to  facilitate  operation  without  reducing  the 
efficiency  of  the  instrument. 

These  suggestions  were  taken  up  by  us  and  an  improved  type  of 
the  Junkers  Calorimeter  designed. 

AMERICAN   JUNKERS    CALORIMETER. 
Tests  by  American  Gas  Institute. 

Having  completed  some  of  these  instruments  with  the  desired 
changes  and  improvements  we  found  they  met  with  general  approv- 
al and  in  1911  we  submitted  one  to  the  American  Gas  Institute  for 
careful  examination  and  test.  The  Committee  on  Calorimetry 
rendered  the  following  report  on  it : 

That  of  the  American  Meter  Company  gives  results 
sufficiently  correct  for  general  use  and  adoption  by 
the  members.  This  instrument  embodies  the  general 
design  of  the  original  Junkers  instrument  and  seems 
to  have  included  the  elements  that  have  given  that 
calorimeter  its  general  high  efficiency.  It  is  modified, 
however,  according  to  the  recommendations  submitted 
in  the  Committee's  Report  for  the  years  1908  and  1909 
and  is  provided  with  accessories  that  read  directly  the 
heating  value,  making  all  measurements  in  English 

Units. 

Later   Tests   by  the   Institute. 

In  1912  a  later  improved  model  was  tested  for  efficiency  with  a 
number  of  other  types  and  the  results  were  very  gratifying  as  shown 
by  Report  of  the  Committee  on  Calorimetry  for  that  year,  from 
which  we  quote : 

(3)  The  American  Meter  Co.'s  Calorimeter. 
The  American  Meter  Co.'s  calorimeter  No.  122  used 
in  this  investigation  was  loaned  by  the  American  Meter 
Co.  of  New  York  City.  In  all  fundamental  principles 
this  calorimeter  is  a  Junkers  calorimeter.  However, 
a  considerable  number  of  minor  changes  have  been 
made  which  facilitate  the  operation  of  the  instrument. 
These  changes  may  be  summarized  as  follows : 


7. 


(1)  Both  thermometers  are  on  the  same  level. 

(2)  Special  gaskets  are  provided  for  securing  the 
thermometers  in  place. 

(3)  The    absorption    chamber    can    be    removed 
from  the  outer  shell  of  the  instrument,  thus  facili- 
tating cleaning  operations. 

(4)  Baffle  plates  are  provided  for  the  burner. 

(5)  The  burner    has  a  flat,  circular  base  so  that 
the  burner  will  remain  in  an  upright  position  when 
unsupported. 

(6)  The  burner  top  screws  on  to  the  stem. 

(7)  An  adjustable  mirror  enables  the  operator  to 
note  the  gas  flame. 

(8)  A  small  plumb  bob  is  provided  for  leveling 
the  instrument. 

(9)  The  position  of  the  damper  is  indicated  by 
a  pointer  and  scale. 

(10)  A  three-way  cock  provides  a  means  of  di- 
recting the  outflowing  water  either  to  the  receiving 
bucket  or  to  the  drain. 

(11)  A  vent  is  provided  to  obviate  the  trapping 
of  air  around  the  three-way  cock. 

Inasmuch  as  the  basic  principles  of  the  instrument 
are  the  same  as  both  forms  of  the  Junkers  calorimeter, 
it  was  not  deemed  necessary  to  work  out  the  proper 
rate  of  combustion  of  the  gas  or  the  proper  relation 
between  the  temperature  of  inlet  water  and  room  tem- 
perature before  making  comparative  tests. 

The  only  work  done  with  this  instrument  was  to 
make  two  series  of  comparative  tests  between  it  and 
the  Junkers  No.  872. 

Conditions  of  Tests. 

Both  calorimeters  were  operated  under  identical 
conditions,  these  being  the  standard  conditions  for  the 
operation  of  the  old  form  of  Junkers  Calorimeter,  as 
previously  determined  in  this  investigation.  Both 


calorimeters  were  operating  continuously  and  simul- 
taneously throughout  each  series  of  tests.  Baffle  plates 
were  placed  upon  the  stems  of  both  calorimeter 
burners.  Natural  draft  used. 

(Here  follow  details  of  tests.) 

Summary  of  Results. 

From  the  above  series  of  tests  the  following  con- 
clusions can  be  drawn: 

(1)  When  operated  under  the    standard    condi- 
tions for  the  old  type  of  the  Junkers  calorimeter  the 
American  Meter  Co.'s  calorimeter  gives  the  same 
efficiency  as  the  Junkers  calorimeter. 

(2)  All  of  the  changes  enumerated  at  the  begin- 
ning of  heading  (3)  appear  to  be  advantageous,  and 
can  truly  be  termed  ''improvements." 

Quoting  again  from  the  Committee's  report: 

A  gas  calorimeter  will  give  various  results  depend- 
ent upon  the  conditions  of  operation,  and  it  is  essential 
that  the  proper  working  conditions  of  each  type  of 
calorimeter  be  known.  Unless  the  calorimeter  is  oper- 
ated under  proper  conditions,  the  heating  values  de- 
termined will  be  unreliable. 

The  standard  conditions  referred  to  as    in    testing    the  original 
Junkers  type  were  as  follows : 

The  rate  of  flow  of  gas  was  seven  (7)  cubic  feet  per 
hour:  the  difference  in  temperature  between  the  inlet 
and  outlet  water  was  from  15  to  16  degrees;  room 
temperature  was  75  degrees.  In  this  and  all  subse- 
quent tests  with  the  Junkers  No.  872,  the  damper  in 
the  exhaust  outlet  was  closed,  because  it  had  been 
found  in  previous  investigations  that  for  this  particular 
instrument  higher  results  could  be  obtained  with  the 
damper  closed  than  with  it  open,  which  indicated  that 
combustion  was  perfect  with  the  minimum  excess  of 
air. 


10 


GENERAL    DESCRIPTION    AND    IMPROVEMENTS. 

The  general  design  of  the  instrument  is  shown  in  the  line  cuts 
opposite  giving  sectional  views  and  in  the  illustrations  of  complete 
sets  of  apparatus  herein. 

The  calorimeter  jacket  is  constructed  of  polished  sheet  copper, 
tinned  inside  and  nickeled  outside  to  prevent  radiation  of  heat. 
The  tubes  are  of  the  best  quality  copper,  tinned. 

The  most  important  improvements  made  in  this  part  of  the  ap- 
paratus are  these: 

Three-way  cock  on  outlet  weir,  so  water  can  be  readily  diverted 
to  waste  or  pail, 

Baffle  plates  fitted  to  the  burner, 

Two  sizes  of  burner  tips  provided,  these  being  set  in  sockets 
which  screw  on  the  burner, 

Burner  constructed  with  base  to  stand  on  when  withdrawn  from 
instrument, 

Mirror  for  observing  the  flame,  making  it  unnecessary  to  with- 
draw the  burner  for  the  purpose,  and  enabling  the  operator  to 
properly  adjust  the  air  supply, 

Water  thermometers  set  close  together  and  at  the  same  level, 

Thermometers  set  in  screw  sockets  instead  of  rubber  corks,  so 
bulbs  can  always  be  kept  at  the  same  depth,  reducing  the  liability 
of  breakage  in  use. 

Exhaust  tube  fitted  with  damper  on  the  axis  of  which  is  a  hand 
moling  over  a  graduated  arc,  thus  enabling  the  operator  to  observe 
the  exact  position  of  the  damper  at  all  times  and  re-set  it  correctly, 

A  small  plumb  bob  hung  from  the  side  of  the  instrument  to  level 
it.  avoiding  the  necessity  of  placing  a  level  against  the  different 
sides  of  the  body, 

The  body  put  together  with  screws  instead  of  being  soldered,  so 
that  it  can  be  taken  apart  and  a«v  trouble  remedied  or  any  part 
cleaned. 


11 


COMPLETE   OUTFITS. 

The  complete  apparatus  and  accessories  are  listed  in  sets  as  fol- 
lows and  can  be  furnished  as  desired : 

No.  300  Set. 

Calorimeter  complete  with  all  improvements  previously  enumer- 
ated. 

2 — 18"  highest  grade  calorimeter  thermometers  for  water,  made 
by  Hohmann  &  Maurer  Mfg.  Co.,  to  specifications  of  Committee 
on  Calorimetry  of  the  American  Gas  Institute,  graduated  in  tenths 
of  a  degree  Fahrenheit  and  furnished  with  telescopic  sights  and 
manufacturers'  certificates  of  comparison  with  Bureau  of  Standards 
certified  thermometer. 

A  high  grade  special  exhaust  thermometer. 

Tinned  brass  wet  test  meter  Xo.  613  type,  1/10  cu.  ft.  per  revo- 
lution, index  reading  I/ 1000th  of  a  cu.  ft.  to  100  cu.  ft.,  fitted  with 
thermometer,  levels,  leveling  screw  feet  and  outside  waterline  gauge 
with  marker  of  special  design  approved  by  the  U.  S.  Bureau  of 
Standards  for  accuracy  and  stability. 

Wet  regulator  of  tinned  brass,  nickeled  outside,  with  pressure 
gauge  fitted  with  nickeled  scale. 


12 


Specially  made  equal  arm  balance  weighing  to  one-thousandth 
of  a  Ib.  with  1/10  Ib.  beam,  agate  bearings  and  forked  pailholder, 
arranged  to  balance  the  empty  pail. 

Two  copper  water  pails  tinned  inside,  for  weighing  the  water. 

Set  of  cylindrical  brass  weights. 

100  cc.  glass  graduate  for  condensation. 

12  ft.  pure  rubber  tubing. 

Correction  table  for  temperature  and  pressure. 

No.  301   Set. 

Including  No.  300  set  with  the  following  additions  and  accessories 
which,  while  not  necessary  for  accurate  operation,  add  to  its  con- 
venience and  are  very  desirable. 

Very  fine  equal  arm  balance  with  agate  bearings,  brass  weight 
plate,  Jorked  pailholder,  one-tenth  pound  beam,  weighing  to  the 
thousandth  part  of  a  pound,  adjusted  to  balance  the  empty  pail  and 
furnished  with  a  fine  set  of  brass  weights  with  lifting  knobs  in 
block. 

Brass  casings  for  the  water  thermometers,  design  as  suggested 
by  the  Bureau  of  Standards  to  prevent  accidental  breakage  as  far 
as  possible  without  affecting  accuracy  or  making  reading  difficult. 

Six  inch  Siphon  Pressure  Gauge  for  use  on  meter  or  gas  supply 
line. 

Meter  fitted  with  bell,  ringing  automatically  at  each  revolution 
of  large  pointer,  indicating  the  registration  of  1/10  cu.  ft.  of  gas 
without  the  operator  having  to  watch  the  meter. 

Heat  Value  Computer,  designed  and  patented  by  the  United  Gas 
Improvement  Co.,  which  saves  much  time  in  calculation  of  results 
and  prevents  errors. 

Record  card  loose-leaf  binder  with  25  card  forms  on  which  to 
enter  results  of  tests. 


13 


No.  302  Set. 

We  have  also  designed  a  nickeled  stand  as  illustrated  for  mount- 
ing the  meter  above  the  governor.  This  saves  space  and  gives  the 
apparatus  a  very  neat  appearance,  the  meter  in  this  model  being 
enameled  white  and  all  gas  connections  made  with  flexible  metal 
tubing. 

This  set  includes  the  No.  301  set  with  this  stand,  etc.,  as  de- 
scribed. 


14 


ACCESSORIES. 

Wooden  Carrying  or  Packing  Cases,  strongly  made,  can  be 
furnished  in  sets  of  2  to  contain  the  entire  apparatus. 

Leatheroid  Trunks  can  also  be  furnished  for  the  use  of  trav- 
eling inspectors  to  further  protect  the  apparatus  when  packed 
for  shipment  in  the  wooden  cases. 

Barometer.  We  recommend  as  the  most  reliable  and  suitable 
for  use  with  the  calorimeter  outfit  the  Mercurial  Observatory  Bar- 
ometer, Weather  Bureau  type,  which  can  be  furnished  on  request. 
This  is  fitted,  unless  otherwise  ordered,  with  a  scale  graduated  in 
inchs  and  tenths  and  with  the  1/100"  Vernier  reading  to  thou- 
sandths of  an  inch.  It  can  also  be  furnished  with  scale  in  milli- 
metres or  inches  and  millimetres. 

Hygrometer.  The  Hygrodeik  is  the  ideal  Hygrometer  for  all 
industrial  or  domestic  uses.  It  is  wet  and  dry  bulb  hygrometry 
minus  the  tables  and  computation.  The  chart  is  a  condensed,  graphic 
presentation  of  all  the  facts  given  in  the  Hygrometer  tables.  While 
complicated  in  appearance,  it  is  simplicity  itself.  This  chart  was 

plotted  from  standard  tables 
compiled  for  use  with  the 
Mason  (wet  and  dry  bulb) 
Hygrometer,  and  can  be  relied 
upon  as  being  correct.  The 
lines  on  the  chart  are  adapted 
to  show  graphically  the  Rela- 
tive Humidity,  Dew  Point, 
absolute  amount  of  moisture 
present  and  the  weight  of 
water  in  each  cubic  foot  of 
air,  expressed  In  grains. 

Testing  Bottle.  For  fre- 
quent and  accurate  testing  of 
the  meter  it  is  best  to  use  a 
1/10  cu.  ft.  bottle.  This  is 
made  of  polished  copper  and 
is  mounted  with  a  copper  tank 
fitted  with  thermometer  on  a 
wooden  stand  as  illustrated 
(Cat.  No.  202).  It  is  fur- 
nished with  Bureau  of  Stand- 
ards certificate  of  accuracy. 


15 


AUTOMATIC  GAS  SHUT-OFF. 

Having  had  called  to  our  attention  many  instances  of  injury  to- 
calorimeters  occurring  through  the  water  supply  from  the  tank 
running  out  while  the  gas  continued  burning,  we  have  devised  a 
shut-off  valve  for  the  gas,  mounted  on  stand  as  illustrated,  this 
valve  being  open  while  the  water  in  the  tank  remains  at  sufficient 
height  but  closing  automatically  and  cutting  off  the  gas  supply  by 
connection  with  a  ball  float  in  the  tank  when  the  water  runs  too  low. 


AUTOMATIC  $A5  VALVE 
TOR 


THE  AHERICAK  METER  CO. 


17 


TESTS  BY  PUBLIC  SERVICE  COMMISSION  NEW  YORK 

We  have  had  a  number  of  our  calorimeters  tested  by  the  Public 
Service  Commission  for  the  Second  District,  State  of  New  York, 
for  use  by  gas  companies  in  this  State,  although  the  testing  of  eas 
for  heat  value  is  not  compulsory  as  yet.  The  last  report  of  effi- 
ciency as  made  to  the  gas  company  purchasing  the  calorimeter,  of 
which  we  obtained  a  copy  by  courtesy  of  the  Commission,  is  as 
follows : 

Efficiency    99.8% 

Gas  Rate  6  ft.  per  hour 

Damper  closed 

Water  Quadrant  60-^ 

FAVORABLE  FEATURES  AND  GUARANTEE. 

One  of  the  particularly  favorable  features  in  this  calorimeter  is 
that  there  are  very  small  variations  in  the  temperature  of  the  outlet 
water  during  a  run  of  tests. 

We  have  been  unceasing  in  our  efforts  to  increase  in  every  pos- 
sible way  the  efficiency  and  facility  of  operation  of  this  apparatus 
and  have  welcomed  suggestions  from  the  experts  using  it,  so  that 
the  American  Junkers  Calorimeter  is  now  regarded  with  the  greatest 
favor  by  those  interested  in  the  gas  industry  generally  and  is  in 
continuous  use  in  the  various  works  controlled  by  the  large  oper- 
ating companies  throughout  the  country,  as  well  as  with  any  number 
of  small  companies  and  many  of  the  Public  Utility  Commissions, 
State  and  City  Gas  Inspectors. 

It  is  fully  guaranteed  as  to  perfection  of  material  and  workman- 
ship, as  well  as  efficient  action  under  the  proper  working  conditions. 

Inquiries  for  prices  will  be  greatly  appreciated  and  promptly 
replied  to,  with  net  quotations,  which  are  subject  to  change  without 
notice,  in  order  to  meet  fluctuating  cost  conditions  and  cover  im- 
provements and  modifications  of  design  as  they  are  adopted  from 
time  to  time. 


18 


RECOMMENDATIONS  OF 
AMERICAN  GAS  INSTITUTE. 

The  following  extracts  from  the  Supplement  to  Report  of  the 
Committee  on  Calorimetry  of  the  American  Gas  Institute  for  1912 
give  authoritative  information  on  the  testing  of  gas  for  calorific 
value. 

It  will  be  noted  by  comparison  of  the  foregoing  description  of 
our  apparatus  with  the  specifications  given  by  the  Committee  cover- 
ing the  necessary  requirements  which  a  calorimeter  outfit  of  the 
Junkers  type  should  satisfy  that  our  improved  calorimeter  with 
meter,  scale  and  governor  more  than  meet  these  requirements,  so 
that  the  specifications  really  are  a  very  good  detailed  description  of 
it,  with  the  exception  only  that  in  several  respects  our  calorimeter 
sets  are  of  finer  grade  than  the  specifications  require. 

The  heating  value  of  a  gas,  as  indicated  by  the  calorimeter,  when 
operated  according  to  these  instructions,  is  that  defined  and  adopted 
by  the  American  Gas  Institute  and  given  in  Volume  III,  1908, 
page  383,  as  follows : 

''The  heating  value  of  a  gas  is  the  total  heating  effect  produced 
by  the  complete  combustion  of  a  unit  volume  of  the  gas,  measured 
at  a  temperature  of  60  degrees  Fahrenheit,  and  a  pressure  of  30 
inches  of  mercury,  with  air  of  the  same  temperature  and  pressure, 
the  products  of  combustion  also  being  brought  to  this  temperature. 

"In  America  the  unit  of  volume  is  the  cubic  foot  and  we  recom- 
mend that  the  heating  value  be  stated  in  terms  of  British  thermal 
units  per  cubic  foot  of  gas." 

It  is  known  that  the  heating  value  thus  determined  by  the  calori- 
meter and  defined  usually  as  the  gross  heating  value,  is  not  always 
the  same  as  the  theoretical  value,  as  the  percentage  of  humidity 
of  the  atmosphere  introduces  an  error  in  the  reading  of  the  instru- 
ment that  may  make  it  read  slightly  higher,  or  lower,  as  the  case 
may  be. 

This  error  may  be  corrected  so  as  to  make  the  gross  heating  value 
equal  to  the  total  heating  value,  when  the  final  reading  is  obtained, 
by  applying  the  corrections  shown  in  Table  I,  attached,  which  was 
submitted  to  the  Institute  by  Dr.  E.  B.  Rosa,  in  his  paper,  "The 
Legal  Specifications  for  Illuminating  Gas." 


19 


Another  factor  that  influences  to  a  considerable  degree  and  which 
should  also  be  taken  into  consideration,  when  a  correction  is  applied 
for  atmospheric  humidity,  is  the  amount  of  air  admitted  with  the 
gas  into  the  calorimeter.  This  quantity  should  be  enough  to  assure 
perfect  combustion  of  the  gas,  and  maintain  the  excess  air  at  a 
minimum.  It  is  controlled  by  the  position  of  the  damper — in  a 
majority  of  cases — which  will  be  explained  later.  In  a  number  of 
instances,  this  excess  air  approximated  30  per  cent,  for  ordinary 
illuminating  gas,  and  this  figure  is  used  for  average  conditions. 

The  so-called  net  heating  value  of  the  gas  may  be  determined  by 
deducting  from  the  gross  heating  value,  the  latent  heat  of  the  water 
condensed  in  burning  one  cubic  foot  of  gas.  No  correction  for 
atmospheric  humidity  should  be  applied  in  determining  this  value. 

To  facilitate  the  operation  of  calorific  determination  of  gas  in 
commercial  practice,  we  recommend  the  use  of  accessories  express- 
ing the  result  direct  in  English  units.  As  the  British  thermal  unit 
has  been  adopted  as  the  expression  of  heating  value,  and,  as  the 
cubic  foot  of  gas  is  used  as  the  unit  of  volume,  the  heating  value 
of  the  gas  is  therefore  expressed  in  British  thermal  units  or  B.  t.  u.'s 
per  cubic  foot.  If,  therefore,  the  various  measurements  are  made 
with  English  measuring  instruments,  all  inconvenience  of  using  a 
mixture  of  metric  and  English  units,  or  a  reduction  of  a  portion  of 
the  data  from  metric  to  the  English  system  will  be  avoided. 

Therefore,  in  determining  the  calorific  value  of  gas  we  recom- 
mend : 

The  measuring  of  the  gas  in  cubic  feet. 

Taking  all  temperatures  of  air,  gas  and  water  with  Fahrenheit 
thermometers. 

Weighing  or  measuring  the  water  in  pounds  and  hundredths  of 
a  pound. 

Correction  of  the  volume  of  the  gas  to  standard  volume,  as  ex- 
pressed when  measured  at  a  temperature  of  sixty  (60)  degrees 
Fahrenheit,  and  barometric  pressure  of  thirty  (30)  inches  of  mer- 
cury. 

Expressing  the  result  of  all  calorific  determinations  in  British 
thermal  units  (B.  t.  u.'s). 


20 


SPECIFICATIONS  TO  BE  ADOPTED  IN  SELECTION  OF 

INSTRUMENT. 

(From  Report  of  American  Gas  Institute.) 

The  following  instructions  cover  the  precautions  to  be  taken  in 
selecting  and  operating  calorimeters  of  the  Junkers  type,  which  are 
those  in  general  use  throughout  this  country. 
Calorimeters  of  Junkers  Type. 

The  calorimeter  proper  should  be  an  instrument  that  transmits 
directly  the  heat  evolved  by  the  burning  gas  to  a  quantity  of  water. 
The  calorimeter  should  be  accompanied  by  accessories  that  shall 
measure  definitely  the  gas  burned,  the  water  heated,  and  the  tem- 
peratures of  the  gas,  water,  air  and  exhaust  products. 

The  apparatus  should  be  designed  to  give  a  constant  head  of 
water  on  the  calorimeter.  This  head  should  be  maintained  by  hav- 
ing a  weir  overflow  on  the  inlet  at  some  distance  above  the  top  of 
the  calorimeter,  and  a  weir  overflow  at  the  outlet.  The  rate  of  water 
flow  through  the  calorimeter  should  be  capable  of  regulation  and 
adjustment. 

The  calorimeter  should  be  so  built  that  the  water  will  circulate 
freely,  and  will  be  equally  distributed  throughout  the  apparatus. 
Baffle  plates  should  be  so  arranged  that  the  water  will  be  thoroughly 
mixed  before  coming  in  contact  with  the  bulb  of  the  outlet  ther- 
mometer, insuring  a  correct  average  reading.  The  design  should 
be  such  that  air  pockets  cannot  form  in  the  water  space  of  the 
calorimeter. 

The  calorimeter  should  be  preferably  made  of  bright  polished 
metal,  air  jacketed  in  all  its  parts. 

There  should  be  a  damper  in  the  exhaust  gas  flue  which  can  be 
easily  adjusted,  and  made  to  control  the  amount  of  excess  air 
passing  through  the  calorimeter. 

The  calorimeter  should  be  mounted  at  a  height  sufficient  to  make 
it  easy  to  put  the  burner  in  place,  and  on  legs  with  a  spread  great 
enough  to  insure  a  firm  base. 

It  may  prove  desirable  in  practice  to  have  water  thermometers 
on  the  same  level,  to  facilitate  readings,  as  recommended  by  the 
Calorimetry  Committee  of  the  American  Gas  Institute.  The  open- 
ings for  thermometers  should  be  large  enough  to  easily  insert  the 
thermometers. 


21 


Gas  Meter. 

For  a  meter,  it  is  preferable  to  use  a  wet  meter,  and  one  register- 
ing one-tenth  cubic  foot  of  gas  per  revolution. 

The  large  dial  should  be  divided  into  100  equal  parts,  with  every 
tenth  part  distinctly  marked  to  facilitate  reading.  In  addition  to 
the  large  dial,  there  should  be  a  smaller  dial  to  register  the  number 
of  revolutions  of  the  large  hand ;  this  dial  should  register  tens,  units 
and  tenths  of  a  cubic  foot. 

The  face  of  the  meter  should  be  enameled  and  no  glass  used  on 
the  front,  thereby  preventing  error  due  to  parallax.  The  face  of  the 
meter  should  be  easily  removable,  in  order  to  get  at  the  shaft  and  the 
stuffing  box  on  the  shaft.  This  stuffing  box  should  be  of  a  size 
large  enough  to  be  easily  packed. 

The  large  hand  of  the  meter  should  be  well  pointed,  and  not 
extend  to  the  outer  end  of  graduations  of  the  meter  dial.  The 
meter  should  have  leveling  screws. 

Two  leveling  tubes,  placed  at  right  angles  to  each  other,  should 
be  securely  fastened  to  the  top  of  the  meter. 

The  meter  should  have  an  outside  gauge  glass  showing  the  water 
level.  This  glass  should  not  be  less  than  %  inch,  nor  more  than 
?4  inch,  inside  diameter,  as  it  is  necessary  to  have  the  glass  large 
enough  to  be  readily  cleaned,  and  small  enough  that  the  meniscus 
formed  by  the  water  can  be  accurately  read.  The  openings  from 
the  gauge  to  the  meter  should  be  unobstructed,  and  of  a  size  to 
correspond  with  the  size  of  the  gauge  glass.  A  fixed  point  to  shon 
the  correct  water  level,  reading  to  the  bottom  of  the  meniscus, 
should  be  put  on  the  outside  of  all  water  level  gauge  glasses. 

For  convenience,  a  standard  3-light  meter  union  should  be  used 
on  all  meters,  and  hose  nipples  for  %  inch  hose  should  be  fur- 
nished with  the  unions. 

The  meter  should  be  provided  with  an  opening  for  the  addition 
of  water  when  needed.  This  can  be  done  by  using  a  pet  cock,  with 
a  small  covered  funnel  mounted  on  top,  connected  to  the  top  of 
the  gauge  glass  support. 


22 


An  opening  must  be  left  for  a  thermometer  in  or  near  the  gas 
outlet.  This  thermometer  should  have  a  metal  case  and  read  to 
one  degree  Fahrenheit,  with  a  range  of  from  about  50  to  100  de- 
grees, and  accurate  to  within  one-half  degree. 

An  opening  with  a  plug  connection  should  be  left  on  the  bottom 
of  the  meter  to  drain  it  when  so  desired. 

The  number  of  joints  liable  to  cause  gas  or  water  leakage  should 
be  reduced  to  a  minimum. 

Gas  Pressure  Regulator. 

The  pressure  of  the  gas  when  burning  in  the  calorimeter  should 
be  absolutely  uniform  to  obtain  correct  results,  and  any  small  regu- 
lator that  will  maintain  this  uniform  pressure  will  be  satisfactory. 
We  recommend  the  use  of  a  small  wet  governor,  similar  to  the  one 
supplied  with  the  Junkers  Calorimeter,  placed  between  the  meter 
and  burner.  This  will  give  excellent  regulation,  and  will  operate 
without  chattering.  Such  a  regulator  should  be  constructed  so  as 
to  be  readily  weighted  for  altering  the  delivered  pressure. 

The  gas  delivered  to  the  meter  should  be  governed  by  means  of 
some  form  of  service  governor  so  as  not  to  exceed  a  pressure  of 
about  two  inches,  while  being  measured. 

Burners. 

The  burner  should  be  a  long  tube  Bunsen,  having  a  spreader  on 
top,  and  adjustable  air  mixer  which  can  be  easily  reached  when 
burner  is  in  position  in  the  calorimeter.  The  burner  should  be 
provided  with  a  stop-cock.  The  burner  should  be  attached  to  the 
calorimeter  in  such  a  way  that  the  gas  flame  cannot  impinge  on  the 
interior  body  of  the  calorimeter,  and  when  the  burner  is  set  at  its 
correct  position,  well  up  into  the  combustion  chamber,  it  should  be 
so  fastened  that  it  cannot  be  accidentally  shifted.  The  condition 
of  the  flame  should  be  observable  by  the  operator,  either  directly 
or  by  means  of  a  reflecting  mirror. 

It  has  been  found,  by  investigation,  that  the  adoption  of  suitable 
baffle  plates  attached  to  the  stem  of  the  burner  prevents  some  radi- 
ation of  heat  downward  from  the  combustion  chamber  and  there- 
fore increases  by  several  B.  t.  u/s  the  observed  heating  value,  of 
the  gas. 


23 


Thermometers. 

Accurate  thermometers  are  the  most  important  accessories  to 
correct  calorimetry. 

The  thermometers  for  reading  water  temperatures  should  be  of 
high  grade  quality,  and  should  read  accurately  within  one-tenth  of 
a  degree  Fahrenheit. 

The  thermometers  should  be  graduated  from  60  to  110  degrees 
Fahrenheit,  each  degree  to  be  divided  into  tenths,  with  short,  dis- 
tinct graduations.  The  thermometers  should  be  so  accurately  made 
that  in  ordinary  commercial  work  corrections  may  be  neglected. 
With  each  thermometer  should  be  provided  a  calibration  curve, 
which  should  enable  very  accurate  results  to  be  obtained  whenever 
it  is  deemed  necessary  to  make  these  corrections. 

This  matter  of  high  grade  thermometers  for  calorimetry  work 
has  been  taken  up  with  several  thermometer  makers  by  your  Com- 
mittee, and  thermometers  are  now  being  supplied  that  accord  to  its 
recommendations.  The  thermometers  have  a  range  of  from  60  to 
110  degrees  Fahrenheit,  and  are  graduated  to  one-tenth  degree. 
Some  of  these  thermometers  were  made  having  an  auxiliary  division 
at  32  degrees  Fahrenheit,  which  was  deemed  convenient  for  check- 
ing the  ice  point ;  but  later  it  was  found  advisable  to  omit  this  auxil- 
iary graduation.  These  thermometers  are  carefully  made  and  have 
a  bore  that  is  exceedingly  uniform  and  accurate,  and  are  supplied 
with  most  makes  of  calorimeters. 

The  error  of  one-tenth  degree  above  mentioned  may  seem  to  be  a 
small  matter,  and  it  is  in  most  measures  of  temperature,  but  when 
the  calorific  value  of  an  artificial  gas  is  determined  with  a  rise  in 
the  water  temperature  of  15  degrees  Fahrenheit,  a  difference  of 
one-tenth  degree  means  an  error  of  1/150  of  the  total  heat  of  the 
gas,  or  about  four  (4)  B.  t.  u.  's.  If  the  total  rise  in  temperature 
is  less  than  this  the  error  introduced  is  greater. 

When  doubt  arises  as  to  correctness  of  thermometers,  we  recom- 
mend their  calibration  by  the  National  Bureau  of  Standards  at 
Washington. 

Telescopic  sights  for  reading  thermometers  should  be  provided, 
as  much  more  accurate  readings  can  be  obtained  in  this  way. 


24 


Barometer. 

Corrections  for  variation  in  barometric  pressure  should  be  made 
in  measuring  the  volume  of  the  gas.  This  pressure  should  either 
be  obtained  by  means  of  a  mercury  column  barometer  or  by  a  re- 
cently calibrated  aneroid  barometer.  Where  it  is  possible  barometer 
readings  should  be  checked  occasionally  with  readings  of  the  Gov- 
ernment Weather  Bureau  of  the  city  in  which  the  readings  are  made. 
Where  no  barometer  is  available,  it  may  be  possible  to  get  fairly 
accurate  figures  on  pressure  by  obtaining  from  the  local  Weather 
Bureau  the  barometer  readings  for  the  day,  and  correcting  for 
variations  in  elevation. 

Water  Supply  and  Measurement. 

The  control  of  the  temperature  of  the  water  supply  is  very  im- 
portant in  calorimetry,  and  this  temperature  should  be  approxi- 
mately that  of  the  room  in  which  the  observations  are  being  made. 
Water  obtained  from  an  ordinary  house  piping  system  is  apt  to 
be  variable  in  pressure  and  temperature,  due  to  the  uneven  con- 
sumption in  other  parts  of  the  building,  and  possible  exposure  of 
the  water  main  to  the  extreme  temperatures  of  the  ground  or  atmos- 
phere. This  control  of  temperature  or  pressure  may  be  readily 
obtained  by  providing  a  permanent  water  supply  tank  in  the  upper 
part  of  the  calorimeter  room,  that  will  contain  enough  water  to 
enable  the  readings  for  the  day  to  be  made.  A  flat  tank  of  large 
horizontal  area  is  preferable  to  a  deep  vertical  tank.  The  exposed 
surface  allows  the  water  to  come  to  the  temperature  of  the  room 
more  readily,  while  the  shallow  depth  has  less  effect  on  the  head 
as  the  water  is  being  used.  A  large  galvanized  house  boiler  has  been 
satisfactorily  used  for  this  purpose. 

Should  a  number  of  continuous  readings  be  made  that  will  require 
more  water  than  is  contained  in  the  overhead  tank,  a  simple  coil 
gas  water  heater  may  be  employed  to  raise  the  temperature  of  the 
water  supply  to  the  overhead  tank,  so  that  it  will  enter  this  tank 
^t  approximately  the  temperature  of  the  room.  The  tank  will  then 
act  as  an  equalizer  and  assist  in  maintaining  a  uniform  temperature 
and  pressure  of  water  entering  the  calorimeter. 

Water  may  be  collected  and  weighed  in  thin  sheet  metal  con- 
tainers, holding  about  nine  (9)  pounds  of  water.  This  size  con- 
tainer will  hold  all  the  water  required  in  burning  0.2  of  a  cubic  foot 


25 


of  ordinary  illuminating  gas,  with  a  range  of  about  fifteen  (15) 
degrees  Fahrenheit  in  temperature  between  the  inlet  and  outlet 
water.  The  scales,  or  balance,  employed  should  have  a  capacity  of 
at  least  ten  pounds,  should  read  to  1/100  of  a  pound,  and  should 
be  calibrated  and  made  correct. 

Should  it  be  desired  to  measure  the  water  volumetrically,  instead 
of  weighing  it,  graduated  vessels  may  be  employed  that  will  read 
accurately  the  water  passed  through  the  calorimeter  to  within  1/100 
of  a  pound.  But  the  use  of  such  graduates  introduces  other  errors 
that  should  be  avoided  if  possible. 

Gas  Piping  and  Tubing. 

Gas  connections  for  a  calorimeter  should  consist  of  metallic 
piping  or  tubing  where  possible;  rubber  tubing,  however,  is  gen- 
erally found  most  convenient  to  use  in  temporary  work,  but  in  all 
cases  the  lengths  used  in  conducting  the  gas  should  be  as  short  as 
possible,  and  they  should  be  thoroughly  saturated  with  gas  before 
a  test  is  made. 

Calorimeter  Cabinet. 

To  facilitate  the  operation  of  the  calorimeters  at  the  various  i^a.* 
plants,  the  calorimeters  should  preferably  be  installed  in  a  cabinet, 
similar  to  that  recommended  in  the  Report  of  the  Calorimetry  Com- 
mittee as  contained  in  the  American  Gas  Institute  Proceedings,  Vol. 
IV.,  1909,  pages  205  and  206.  This  sketch  represents  a  typical  cabi- 
net, suitable  for  use  in  some  convenient  building,  either  at  the  gas 
works  or  gas  office,  and  of  such  a  design  that  when  the  calorimeter 
is  once  placed  and  connected  up,  it  may  be  kept  clean,  protected 
and  ready  for  use  at  all  times.  The  details,  however,  may  be  modi- 
fied to  suit  local  circumstances. 

In  construction,  the  cabinet  should  be  made  as  dust  tight  as  prac- 
ticable. Where  there  is  not  enough  head  room  for  a  vertical  sliding 
door,  horizontal  sliding  or  folding  doors  may  be  substituted.  This 
cabinet  should  provide  for  an  overhead  water  tank,  and  may  be 
most  conveniently  located  adjacent  to  a  sink  and  water  supply. 

The  gas  supply  line  to  the  calorimeter  should  have  a  purging  con- 
nection. All  cocks  controlling  the  gas  and  water  supply  should  be 
inside  of  the  cabinet,  and  the  cabinet  should  be  kept  closed  and 
locked  when  not  in  service. 


26 


This  cabinet  should  not  be  near  any  gas  flame,  heating  register 
or  other  radiator ;  direct  sunlight  should  not  be  allowed  to  strike 
upon  it,  but  the  thermometers  and  meter  shall  receive  sufficient  re- 
flected artificial  light  to  enable  them  to  be  easily  read.  Since  drafts 
must  be  rigorously  excluded,  it  is  better,  wherever  possible,  to  set 
aside  a  room  solely  for  the  use  of  the  calorimetric  outfit. 

The  adoption  of  such  an  installation  will  enable  a  calorific  read- 
ing of  the  gas  to  be  made  in  a  very  short  time,  and  will  warrant 
the  best  of  care  being  taken  of  the  calorimeter  and  its  accessories. 


27 


DIRECTIONS  FOR  ERECTING  AND  OPERATING. 
(From  Report  of  American  Gas  Institute  with  Addenda.) 

On  unpacking  the  calorimeter  see  that  all  parts  are  received  and 
in  good  condition.  Clean  it  inside  and  outside  and  be  sure  it  is 
free  of  all  packing  material. 

Set  up  the  apparatus  as  shown  in  cuts  of  the  different  sets. 

Screw  on  the  inlet  water  pipe  and  see  that  the  air  vent  tube  is  in 
its  place  in  this  pipe. 

Level  the  calorimeter  by  means  of  the  screw  feet  and  plumb-bob. 

Connect  the  center  hose  nipple  on  the  inlet  weir  with  rubber 
tubing  to  the  water  supply  and  the  side  connection  to  the  sink  to 
carry  away  the  overflow. 

Connect  the  tubing  for  water  running  to  weighing  pail  to  the 
vertical  nipple  on  the  3-way  cock  on  the  outlet  weir  and  for  the 
waste  to  the  side  nipple. 

Handle  the  thermometers  with  the  greatest  of  care. 

Screw  the  32°  to  100°  thermometer  on  the  inlet  water  pipe  and 
the  60°  to  110°  thermometer  on  the  top  of  the  instrument  for  the 
outlet  water.  Screw  the  small  thermometer  in  place  on  the  exhaust 
flue. 

Place  the  two  telescopic  sights  in  position  on  the  water  ther- 
mometers, being  very  careful  not  to  break  them  off  by  pressure 
against  the  sights. 

Connect  the  meter  to  the  governor  and  the  governor  to  the  burner 
with  short  pieces  of  rubber  tubing  (Sets  Nos.  300  and  301),  or  with 
flexible  metal  tubing  having  coupled  ends  (Set  No.  302). 

The  calorimeter  should  be  set  up  in  a  quiet,  light  and  well  venti- 
lated room  or  cabinet,  which  is  free  from  draughts  and  in  which 
the  temperature  can  be  maintained  constantly  at  not  less  than  sixty 
degrees  Fahrenheit.  The  room  should  be  provided  with  a  sink  and 
with  a  good  supply  of  running  water.  It  is  advisable  to  have  a 
large  shallow  overhead  covered  tank,  from  which  the  water  supply 
can  be  taken.  Should  the  tank  capacity  be  small  and  not  hold 
enough  water  for  a  prolonged  series  of  readings,  a  small  gas  water 


28 


heater  may  be  employed  as  already  noted  to  bring  the  water  to 
approximately  the  room  temperature.  It  is  desirable  to  use  water 
in  the  calorimeter  that  is  clear  and  free  from  suspended  matter, 
therefore,  a  filter  should  be  installed  in  the  water  supply  line  before 
it  enters  the  overhead  tank. 

If  only  a  single  test  is  desired,  gas  may  be  taken  from  the  house 
piping,  but  if  an  average  value  is  required,  a  small  gas  holder,  or 
averaging  tank,  should  be  used,  and  the  gas  flowing  into  the  holder 
adjusted  to  a  rate  of  flow  to  just  fill  it  in  the  time  during  which 
the  sample  is  to  be  taken.  Care  should  be  taken  to  have  a  short 
service  to  this  holder  in  order  that  an  average  sample  of  gas  may 
be  obtained,  and  if  the  sample  be  taken  from  a  line  on  which  there 
is  no  considerable  consumption,  see  that  this  line  is  thoroughly 
purged  before  sampling.  It  is  recommended  that  the  gas  be  metered 
at  a  pressure  not  to  exceed  two  inches  of  water;  if  this  is  not  ob- 
tainable, it  is  advisable  to  insert  a  holder  or  diaphragm  governor 
in  the  supply  line  to  reduce  the  pressure  to  within  this  limit. 

Set  up  the  calorimeter  so  that  the  overflow  and  outlet  water  can 
be  easily  led  to  the  sink.  Make  water  connections  with  rubber 
tubing,  being  careful  not  to  cramp  the  tubing.  To  avoid  air  cur- 
rents caused  by  the  movement  of  the  observer's  body,  set  up  the 
calorimeter  so  that  the  water  supply  and  waste  may  be  easily  ad- 
justed and  that  all  temperatures  may  be  readily  observed.  Lead 
the  outlet  water  to  a  waste  funnel  supported  a  little  above  the  top 
of  the  copper  or  glass  container  used  in  collecting  the  water,  so  that 
the  water  can  be  shifted  from  the  funnel  to  the  container  and  back 
without  spilling. 

Set  up  the  gas  meter  facing  the  observer  and  level  it  carefully. 
Then  adjust  the  water  level  of  the  meter,  both  inlet  and  outlet  being 
open  to  the  air.  To  do  this,  remove  the  plug  from  the  dry  well,  open 
the  funnel  cock  and  disconnect  the  tubing  on  the  outlet  of  the  meter. 
Add  water  through  the  funnel  or  remove  by  the  cock  under  the 
gauge  glass  until  the  lowest  edge  of  the  meniscus  just  touches  the 
scratch  on  the  gauge  glass,  or  is  even  with  the  fixed  marker.  If  the 
meter  has  been  filled  with  fresh  water  the  gas  must  be  allowed  to 
burn  at  least  two  hours  before  making  a  test.  When  the  water  in 
the  meter  is  saturated  with  gas,  twenty  minutes  should  be  sufficient, 


29 


Fill  pressure  regulator  with  water,  about  £4  full,  then  connect  it 
to  the  calorimeter  burner.  Metallic  tubing  is  preferable,  but  when 
rubber  tubing  is  used  to  connect  meter,  pressure  regulator  and 
burner,  connections  should  be  as  short  as  possible,  and  should  be 
saturated  with  the  gas. 

Turn  on  gas  and  allow  it  to  burn  for  5  to  10  minutes  with  the 
burner  on  the  table.  Shut  off  gas  at  burner  and  watch  hand  on 
meter  for  leakage.  Be  sure  that  all  leaks  are  stopped  before  attempt- 
ing to  make  a  test.  Start  water  running  through  the  calorimeter  at 
a  rate  of  about  three  pounds  per  minute.  Then  regulate  the  gas  to 
flow  at  the  rate  of  four  to  seven  feet  an  hour,  as  may  be  found  by 
experiment  to  give  the  highest  result  with  the  gas  to  be  tested, 
admitting  enough  air  through  the  burner  so  that  the  flame  shows  a 
faint  luminous  tip,  then  insert  the  burner  as  far  up  into  the  com- 
bustion chamber  as  the  bracket  permits,  and  observe  again  the  con- 
dition of  the  flame  to  see  that  it  is  all  right,  using  a  mirror. 

The  excess  of  air  passing  through  the  calorimeter  is  controlled 
somewhat  by  the  position  of  the  damper  in  the  exhaust  port,  and  the 
best  results  are  obtained  by  having  the  excess  air  as  low  as  possible 
and  still  maintaining  complete  combustion  of  the  gas.  To  determine 
this  position  of  the  damper,  some  experimentation  may  be  necessary. 
Operate  the  calorimeter  until  a  thermal  balance  is  established  on  the 
inlet  and  outlet  water  thermometers.  Start  with  the  damper  closed, 
then  open  slightly,  observing  carefully  the  outlet  thermometer. 
When  this  thermometer  reads  at  a  maximum — or  in  other  words, 
when  the  greatest  rise  in  temperature  is  given  to  the  water.  \v'  iri 
is  presumably  passing  through  the  calorimeter  uniformly — the 
damper  is  in  approximately  the  correct  position  for  the  amount  of 
gas  being  burned,  and  the  excess  air  necessary  for  perfect  combus- 
tion is  at  a  minimum. 

Water  should  be  regulated  so  that  there  is  a  difference  between 
the  inlet  and  outlet  temperatures  of  about  15  degrees  Fahrenheit. 
The  temperature  of  the  inlet  water  should  vary  but  little  when  an 
overhead  tank  is  used  and  the  water  maintained  at  room  tempera- 
ture. Be  sure  that  both  overflows  are  running. 

Before  making  the  test,  the  barometer,  temperature  of  the  gas  at 
the  meter,  temperature  of  room  and  temperature  of  exhaust  products 
should  be  recorded.  It  is  desirable  to  have  the  temperature  of  the 
inlet  water  and  temperature  of  exhaust  products  as  nearly  as  pos- 


30 


sible  at  room  temperature,  in  order  to  establish  more  nearly  a 
thermal  balance — the  difference  in  these  temperatures  should  never 
exceed  five  degrees. 

Next  allow  the  gas  to  burn  in  the  calorimeter  until  a  thermal 
balance  is  established,  or  until  there  is  the  least  change  in  the  inlet 
and  outlet  waters. 

The  test  may  now  be  started  by  shifting  the  outlet 
water  by  the  three-way  cock  from  the  funnel  to  the  con- 
tainer just  as  the  large  hand  on  the  meter  passes  the 
zero  point.  Readings  are  then  made  of  inlet  and  outlet  ther- 
mometers, making  the  readings  as  rapidly  as  the  observer  is  able  to 
record  them  during  the  consumption,  preferably  of  two-tenths  of  a 
cubic  foot  of  gas.  At  least  ten  readings  should  be  made  of  both 
inlet  and  outlet  water  temperatures.  Water  is  again  shifted  from  the 
container  to  the  waste  funnel  as  the  hand  passes  the  zero 
point  the  second  time.  Water  is  then  weighed  or  measured. 
The  uncorrected  heating  value  per  cubic  foot  is  obtained  by  multi- 
plying the  difference  of  the  averages  of  inlet  and  outlet  tempera- 
tures, by  the  number  of  pounds  of  water  and  by  dividing  by  two- 
tenths.  This  quantity  is  divided  by  the  correction  factor  for  baro- 
meter and  temperature,  obtainable  from  tables,  to  give  the  heating 
value  at  30  inches  pressure  and  60  degrees  Fahrenheit.  The  weight 
or  contents  of  container  should  be  obtained  while  the  inside  is  wet. 
This  may  be  done  by  filling  it  with  water,  emptying  and  shaking 
for  about  five  seconds  in  an  inverted  position.  This  will  do  away 
with  any  correction  where  several  consecutive  tests  are  required 
with  same  container. 

A  second,  and  perhaps  a  third  test  is  advisable,  and  these  should 
be  made  without  disturbing  the  existing  conditions,  provided  all 
readings  are  within  the  above  prescribed  limits.  In  practice  the 
operator  should  get  consecutive  results  on  the  same  holder  of  gas 
within  ten  (10)  B.  t.  u.'s.  Under  such  conditions  an  average  of  the 
results  may  safely  be  taken. 
Results  as  Obtained  by  Calculation. 

The  method  of  calculating  the  calorific  value  of  the  gas  from 
the  observations  indicated  is  very  simple  when  all  readings  are  made 
in  English  units,  as  recommended,  and  entered  in  some  form  con- 
veniently arranged.  A  simple  record  sheet  is  shown  herewith,  a 
convenient  size  for  which  is  five  by  eight  inches. 


31 


JVb. 


GAS  CALORIMETER  READINGS 


PLACE  OF  TEST 


DATE 


Kind  of  Gas  
Calorimeter,  Kind  — 
Barometer  Reading  ..._ 
Temperature  of  Gas  - 
Correction  Factor  — 
Temp,  of  Atmosphere 
Temperature   of   Exhi 
Condensed  Water  Coll 
Time  one  Rev.  of  Met 
Gas  Consumed  Dur'g  r 
Rate  of  Combustion  . 
Weight  of  Water 

TIME 

TIME 

FIME 

* 

^ 



lUSt- 

scted 

ST  — 

Pestt 

* 

Per  cent.  Atmos.  Humidty 

TEMPERATURES    OF 
WATCH 

1 

INLET        OUTLET 

INLET 

OUTLET 

INLET 

OUTLET 

READ    AT    LEAST 
TEN  TIMES  DUR- 
ING   TWO    REVO- 
LUTIONS   OF 
METER    HAND 

I    .     . 

2 
3 
4 

5 
6 

Z. 
8 
9 
10. 

Average  Temperature 
Thermometer  Correct 
Actual   Temp.   
Rise  in  Temp.  

ton™. 

* 

. 

___.!  

B.  T.  U.  Recorded  — 
Cor.  for  Atmos.  Hum: 
B.  T.  U.  Corrected  .. 

dity 

In  using  Heating  Value  Computer,  take  Figures  Indicated  by  Asterisk* 


OBSERVER 


32 


The  averages  of  the  inlet  and  outlet  water  temperatures  are 
determined  and  necessary  corrections  for  thermometer  errors  are 
made.  The  difference  in  these  averages  should  give  the  rise  in 
temperature  of  the  water.  This  rise  in  temperature  of  the  water  is 
then  multiplied  by  the  number  of  pounds  of  water  passed  through 
the  calorimeter  during  the  test. 

The  product  of  these  two  is  then  divided  by  the  quantity  of  gas 
burned — 0.2  of  a  cubic  foot.  This  quotient  will  give  the  heating 
value  of  one  cubic  foot  of  gas  in  B.  t.  u.'s  at  the  indicated  tempera- 
ture and  barometric  pressure.  To  correct  this  to  60  degrees  Fah- 
renheit and  30  inches  pressure,  divide  by  the  "Correction  Factor" 
for  the  indicated  temperature,  and  pressure  as  obtained  from  some 
standard  table.  [Printed  on  card  sent  with  apparatus.]  The  final 
result  will  be  the  corrected  heating  value  of  the  gas  tested,  in 
B.  t.  u.'s. 

Expressing  the  above  in  a  formula  we  have : 

W  X  T 
B.  t.  u.'s  per  cubic  foot=-        — . 

G 

W  =  weight,  in  pounds,  of  water  passed. 

T  =  the    average    difference    in    temperature,    in    degrees 
Fahrenheit,  between  inlet  and  outlet  water. 

G  =  corrected  volume  of  gas  burned,  in  cubic  feet. 

The  correction  for  atmospheric  humidity  is  made  finally,  if  so 
desired. 

Use  of  Computer. 

The  labor  of  making  the  calculations  for  determining  the  heating 
value  from  observations  of  a  calorimeter  may  be  lessened  by  the 
use  of  a  heating  value  computer.  The  computer  consists  of  a  circu- 
lar slide  rule,  with  divisions  corresponding  to  the  readings  made  or 
the  calorimeter.  This  computer  gives  the  corrected  heating  value  oi 
a  cubic  foot  of  gas  in  B.  t.  u.'s,  having  the  barometric  pressure  and 
temperature  of  the  metered  gas,  and  the  difference  in  temperature 
between  the  inlet  and  outlet  water,  and  the  pounds  of  water  passed. 
This  computer  is  designed  to  operate  within  the  limits  of  from  300 
to  800  B.  t.  u.'s.  Should  a  gas  of  a  lower  or  higher  heating  value  be 
measured,  the  computer  can  still  be  used  by  dividing  or  multiplying 


33 


one  or  the  other  of  the  factors  in  its  computation.  A  cut  of  this  com- 
puter can  be  found  on  page  373,  Vol.  Ill,  Proceedings  of  the  Ameri- 
can Gas  Institute. 

Care  of  Instruments. 

The  calorimeter,  being  a  delicate  and  sensitive  instrument,  should 
be  very  carefully  cared  for  when  not  in  use.  If  the  instrument  is 
set  up  permanently,  provision  should  be  made  that  it  be  not  disturbed 
by  anybody  except  the  operator.  If  the  instrument  is  not  erected 
permanently,  when  dismantled  it  should  be  carefully  cleaned  inside 
and  out  and  the  thermometers  removed  and  carefully  packed  in 
cotton. 

It  is  advisable  to  inspect  the  calorimeter  periodically  to  see 
whether  the  interior  of  the  combustion  chamber  and  tubes  are  free 
from  carbon  deposits  and  corrosion.  This  should  be  done  once 
every  few  months  and  if  it  is  found  not  to  be  clean,  the  interior  of 
the  combustion  chamber  should  be  washed  or  wiped  out  and  the 
tubes  should  be  cleaned.  The  latter  may  be  easily  freed  of  any 
deposit  by  using  a  wire  brush  cleaning  rod,  similar  to  that  used  in 
cleaning  rifle  barrels. 

It  seems  hardly  necessary  that  instruction  should  be  given  for  the 
care  of  such  an  instrument,  but  certain  precautions  should  be  noted. 

Precautions— "Don'ts." 

Don't  place  lighted  burner  in  calorimeter  when  water  is  not  run- 
ning through  the  calorimeter. 

Don't  shut  off  water  while  gas  is  burning,  but  if  water  is  acci- 
dentally shut  off,  then  shut  off  the  gas  quickly,  to  avoid  breaking 
thermometers. 

Don't  move  suddenly  near  instrument  during  test.  Slight  drafts 
thus  caused  will  vary  outlet  readings  and  vitiate  test. 

Don't  fail  to  check  daily  the  water  level  in  the  gas  meter. 

Don't  forget  to  test  meter  and  all  connections  daily  for  leakages. 

Don't  erect  the  calorimeter  too  close  to  any  heating  or  lighting 
appliances,  where  radiant  heat  might  affect  the  readings. 

Don't  make  the  test  with  the  inlet  water  temperature  over  5 
degrees  above  or  below  the  temperature  of  the  room. 

Don't  fail  to  fill  the  overhead  tank  with  water  when  through 
testing,  so  that  it  will  be  ready  for  the  next  test. 


34 


Note. 

That  an  error  of  one-tenth  degree  f.  in  the  temperature  of  the 
water  means  an  error  of  about  4  B.  t.  u.'s  in  the  gas. 

That  an  error  of  one-hundredth  of  a  pound  of  water  when  burn- 
ing 0.2  of  a  cubic  foot  of  gas  in  the  test  means  an  error  of  about 
0.9  B.  t.  u.  in  the  gas. 

That  an  error  of  one  degree  in  the  temperature  of  the  gas  means 
an  error  of  about  1.8  B.  t.  u.'s. 

That  an  error  of  one-tenth  of  an  inch  in  barometer  reading  means 
an  error  of  about  2  B.  t.  u.'s. 

That  when  metering  the  gas,  each  additional  inch  of  water  pres- 
sure to  which  the  gas  is  subjected  means  an  error  of  about  1.5 
B.  t.  u.'s. 

TO   ADJUST   THERMOMETERS. 

In  case  the  mercury  becomes  lodged  in  the  top  of  the  thermometer, 
up-end  the  instrument,  shake  it  gently  downward  holding  it  in  one 
hand  and  striking  the  upper  end  against  the  palm  of  the  other  until 
the  column  runs  down  and  joins  the  mercury  in  the  top,  then  sud- 
denly reverse  the  position  of  the  thermometer  to  bring  it  top  up  and 
the  mercury  should  all  fall  back  into  place. 

If  the  mercury  is  not  re-united  by  the  above  method  heat  the  bulb 
very  slightly  while  holding  in  the  inverted  position,  holding  a  lighted 
match  or  small  flame  near  it,  being  careful  not  to  overheat.  As  soon 
as  the  sections  join  reverse  the  position  as  above  instructed. 

TO  ADJUST  BALANCE  FOR  WEIGHING  WATER. 

This  is  specially  arranged  to  balance  with  empty  pail  on  scale. 

If  scale  is  out  of  balance,  due  generally  to  the  counters  being  out 
of  level,  it  can  be  balanced  quickly  as  follows : 

Suppose  the  pail  side  is  too  heavy ;  with  pail  on  pail  side  place 
enough  lead  foil  on  the  weight  plate  tc  make  scale  balance;  then 
unscrew  the  weight  plate  and  drop  the  lead  foil  into  the  cup  put 
there  for  the  purpose.  If  scale  is  too  heavy  on  weight  plate  side, 
remove  a  little  of  the  lead  found  in  the  cup.  See  that  the  weight 
plate  is  screwed  down  tightly  in  its  place. 

It  is  best  to  have  pail  side  a  little  heavy,  so  that  the  scale  will  drop 
down  and  rest  there  when  not  in  use.  Never  put  oil  on  any  part  of 
the  scale. 


35 


CORRECTIONS  FOR  ATMOSPHERIC  HUMIDITY. 
(From  Report  of  American  Gas  Institute.) 

This  correction  is  found  to  be  the  greatest  when  the  percentage  of 
humidity  of  the  atmosphere  is  the  lowest.  The  reason  being  that  the 
relatively  dry  air  entering  the  calorimeter  causes  to  be  carried  out 
in  the  exhaust  products  a  larger  amount  of  the  water  in  the  form  of 
a  gas  or  vapor,  that  is  formed  by  the  combustion  of  the  gas,  and 
which  does  not  condense,  and,  therefore,  does  not  give  up  its  latent 
heat  to  the  calorimeter. 

The  humidity  correction  should  correct  for  any  discrepancy  in 
water  vapor  carried  in  by  the  air  and  gas,  compared  with  that  car- 
ried out  by  the  products  of  combustion. 

Owing  to  the  contraction  in  volume,  during  the  combustion  of 
ordinary  illuminating  gas  and  air,  this  discrepancy  is  practically 
nothing  when  the  percentage  of  atmospheric  humidity  is  about  eighty 
per  cent.,  at  normal  temperatures,  and  the  excess  of  air  introduced 
for  combustion  is  about  thirty  per  cent. 

In  correcting  for  atmospheric  humidity  it  is  assumed  that  the  gas 
is  saturated  with  water  vapors — having  passed  through  a  wet  meter. 
This  assumption  might  not  be  absolutely  true,  but  the  percentage  of 
saturation  has  been  found  always  to  be  high,  and  as  the  volume  of 
gas  is  only  about  one-eighth  of  the  mixture,  the  error  involved  may 
be  neglected. 

Table  I. — Corrections  to  Observed  Heat  to  Get  Total  Heat  Value. 

Air,  Gas  and  Exhaust  Must  Be  at  the  Same  Temperature. 

If  7  volumes  of  air  per  volume  of  gas  are  used. 


Humidity 

Room  Temperatures. 

Per  cent. 

65° 

70° 

75° 

80° 

85° 

90° 

10 

+4.8 

+5.7 

+6.7 

+7.9 

+9.2 

+  10.5 

20 

+4.1 

+4.9 

+5.7 

+6.8 

+7.8 

+  9.0 

30 

+3.4 

+4.1 

+4.7 

+5.6 

+6.5 

+  7.4 

40 

+2.7 

+3.2 

+3.7 

+4.5 

+5.2 

+  5.9 

50 

+2-0 

+2.4 

+2.8 

+3.4 

+3.8 

+  4.3 

60 

+  1.3 

+1.6 

+  1.8 

+2.2 

+2.5 

+  2.8 

70 

+0.6 

+0.8 

+0.8 

+  1.0 

+  1.2 

+  1.2 

80 

—0.1 

0.0 

—0.1 

—0.1 

—0.1 

—  0.3 

90 

—0.8 

-0.9 

-1.1 

-1.3 

-1.5 

-  1.9 

100 

—1.6 

—1.8 

—2.0 

—2.4 

—2.8 

—  3.4 

Note — These  corrections  are  expressed  in  B.  t.  u.  's. 


36 


DIRECTIONS  FOR  USE  OF  ACCESSORY  APPARATUS 

Observatory  Barometer. 

To  put  up  the  barometer  for  observation,  suspend  the  barometer 
by  the  ring  in  a  good  light  near  to  and  at  the  left  side  of  a  window 
and,  when  practicable,  in  a  room  not  liable  to  sudden  variations  of 
temperature.  Record  the  temperature  and  then  by  the  screw  lower 
the  mercury  in  the  cistern  until  the  surface  is  in  the  same  plane  with 
the  extremity  of  the  ivory  point,  allowing  ample  time  for  the  mer- 
cury to  fall  to  the  proper  level  in  the  tube.  As  this  extremity  of  the 
point  is  the  zero  of  the  scale,  it  is  necessary  at  each  observation  to 
perfect  this  adjustment.  It  is  perfect  when  the  mercury  just  makes 
visible  contact.  If  the  surface  is  lowered  a  little,  it  is  below  the 
point;  and  if  raised  a  small  amount,  a  distinct  depression  is  seen 
around  the  point.  This  depression  is  reduced  to  the  least  visible 
degree.  A  few  trials  will  show  that  this  adjustment  can  always  be 
made  to  a  thousandth  of  an  inch. 

Never  lower  the  mercury  by  the  screw  much  below  the  ivory 
point  while  the  barometer  is  in  a  vertical  position,  as  when  the 
mercury  is  low  in  the  cistern,  air  will  enter  the  tube  unless  held  at 
an  angle  of  about  45°. 

The  adjustment  effected,  bring  the  lower  edge  of  the  Vernier, 
by  means  of  the  milled  heads,  into  the  same  plane  with  the  convex 
summit  of  the  mercury  in  the  tube.  Looking  through  the  opening, 
with  the  eye  on  a  level  with  the  top  of  the  mercury  in  the  tube, 
when  the  Vernier  tube  is  too  low  the  light  is  cut  off ;  when  too  high 
the  light  is  seen  above  the  top  of  the  mercury.  It  is  right  when  the 
light  is  just  cut  off  from  the  summit,  the  edge  making  a  tangent  to 
the  curve.  An  opal  glass  reflector  placed  behind,  and  also  at  the 
cistern,  will  be  found  to  give  a  more  agreeable  light  by  day  and  is, 
besides,  necessary  for  night  observations ;  the  lamp  being  placed 
before  the  instrument  and  above  the  eye  to  reflect  the  light. 

When  taking  the  barometer  about  the  screw  should  be  run  up 
full  to  seal  the  end  of  the  tube  and  if  to  be  taken  a  considerable 
distance  the  instrument  should  be  carried  in  an  inverted  position. 


37 


Hygrodeik. 

Swing  the  index  hand  to  the  left  of  the  chart,  and  adjust  the 
sliding  pointer  to  that  degree  line  upon  the  chart  which  corresponds 
with  the  degree  of  temperature  shown  upon  the  engraved  stem  of 
the  Wet  Bulb  Thermometer.  Then  swing  the  index  hand  to  the 
right,  until  the  sliding  pointer  intersects  the  curved  line  which 
extends  downward  to  the  left  from  the  degree  line  upon  the  chart 
corresponding  with  the  indicated  temperature  of  the  Dry  Bulb 
Thermometer.  At  this  intersection  the  index  hand  will  point  to  tht 
Relative  Humidity  on  the  scale  at  bottom  of  chart. 

For  example:  Should  the  temperature  indicated  by  the  Wet  lUilh 
Thermometer  be  72°  and  that  of  the  Dry  Bulb  86°,  the  index  hand 
will  indicate  Relative  Humidity  48%  when  the  pointer  rests  on  the 
intersecting  lines  of  72°  and  86°. 

Observe  the  intersection  as  above,  and  follow  the  curved  line 
passing  through  it,  which  runs  from  the  top  downward  to  the  right, 
to  the  point  of  contact  with  the  Dry  Bulb  scale.  The  degree  (65)  at 
ihis  point  on  that  scale  is  the  Dew  Point.  The  figure  at  the  upper 
end  of  this  line  gives  the  absolute  amount  of  water  in  grains  (6.8 
grains)  per  cubic  foot  of  air. 

One-Tenth  Cubic  Foot  Bottle. 

Set  the  bottle  up  on  the  wooden  stand  as  shown  in  illustration  and 
put  in  place  the  two  adjustable  shelves  for  the  tank.  Set  the  tank 
on  the  upper  shelf  and  connect  it  to  the  bottom  of  the  bottle  by  the 
rubber  tube. 

Fill  the  tank  with  water  to  within  2  inches  of  the  extreme  top. 
Set  the  thermometer  in  the  top  of  the  tank  so  that  the  bulb  is  in  the 
water.  Open  the  cock  on  the  bottom  of  the  bottle  and  at  least  one 
cock  on  the  top.  Open  the  cock  on  the  tank,  permitting  the  water 
to  run  slowly  into  the  bottle  until  it  rises  a  little  above  the  index, 
or  marker,  on  the  upper  glass  tube.  Then  lower  the  adjustable  shelf 
on  which  it  stands  until  by  experiment  the  point  is  found  where  the 
water  remains  at  the  exact  level  of  the  top  of  the  marker  on  the 
upper  gauge  glass,  being  at  the  same  level  inside  the  tank. 

Then  place  the  tank  on  the  lower  shelf,  letting  the  water  run  from 
the  bottle  to  the  tank.  Adjust  the  shelf  so  that  the  water  will  remain 
exactly  at  the  level  of  the  top  of  the  marker  on  the  lower  glass  tube, 
being  at  the  same  level  in  the  tank. 

Level  the  meter  and  set  the  waterline  with  precision  as  previously 
explained,  having  the  inlet  and  outlet  open  to  the  air  and  the  tem- 
perature of  air,  water  in  tank  and  water  in  meter  the  same. 


38 


Connect  the  inlet  of  the  meter  by  rubber  tubing-  to  one  of  the 
cocks  at  the  top  of  the  bottle,  closing  the  other  cock. 

Replace  the  tank  on  the  upper  shelf  and  let  the  bottle  fill,  forcing 
the  contained  air  through  the  meter.  Repeat  this  a  few  times,  open- 
ing the  cock  at  top  of  bottle  to  which  the  meter  is  not  connected  for 
air  supply  when  placing  the  tank  on  bottom  shelf. 

Bring  the  large  pointer  on  meter  exactly  to  zero  on  the  dial  by 
turning  to  right,  or  note  its  exact  position  for  a  starting  point. 

Make  several  runs  of  the  bottle  on  the  meter,  noting  the  reading 
after  each  and  observing  the  variation  if  any  from  a  complete  revo- 
lution of  the  large  hand  in  thousandths  of  a  cubic  foot. 

On  taking  the  average  of  these  runs  the  percentage  of  error  is 
expressed  by  the  number  of  thousandths  of  a  cubic  foot  by  which 
the  reading  differs  from  100,  there  being  100  divisions,  or  thou- 
sandths of  a  cubic  foot,  in  one  revolution  of  the  large  circle,  equal 
in  total  to  I/ 10th  of  a  cubic  foot  passed  from  the  bottle.  For  ex- 
ample, if  the  average  shows  a  reading  of  99/1000ths  the  meter 
registers  99/1000ths  of  a  cubic  foot  while  passing  100/lOOOths  and 
is  therefore  1%  slow.  If  it  registers  101/lOOOths  it  is  \%  fast. 


39 


THIS  BOOK  IS  DUE  ON  THE  LAST  DATE 
STAMPED  BELOW 

AN  INITIAL  FINE  OF  25  CENTS 

WILL  BE  ASSESSED  FOR  FAILURE  TO  RETURN 
THIS  BOOK  ON  THE  DATE  DUE.  THE  PENALTY 
WILL  INCREASE  TO  5O  CENTS  ON  THE  FOURTH 
DAY  AND  TO  $1.OO  ON  THE  SEVENTH  DAY 
OVERDUE. 


ttg 


LD  21-100m-12,'43  (8796s) 


Binder 

(iaylord  Bros.,  Inc. 
Stockton,  Calif. 
M.  Reg.  U.S.  Pat.  Off. 


Calorimet 

ry 

DEC  7     M4 

6   ^ 

• 

i 

L  L 

i 
• 

I 



M82511 


THE  UNIVERSITY  OF  CALIFORNIA  LIBRARY 


